An 80-year-old female with a history of arthritis and high blood pressure presents with recurrent lesions and erythema on the palms of her hands and the soles of her feet. On examination, hyperkeratosis, brown macules, and discrete pustules are seen on her palmoplantar surfaces. A fungal culture and serologic tests are unremarkable. Which of the following is most strongly associated with this patient’s condition?

This patient returned from a 4-hour bike ride with a non-blanching purpuric rash on his lower legs that spared the skin compressed by his socks. He had no significant medical history and denied taking medication. Was a bike ride the cause of this eruption?

This patient has been diagnosed with a hereditary (consanguineous) form of palmoplantar keratoderma, a condition characterized by an overproduction of keratin in the palms and soles. The disorder varies in severity and can be complicated by frequent bacterial, viral, and fungal infections. Symptoms are generally managed with the use of emollients and keratolytic agents.

The condition appeared in the entire family due to consanguinity. Consanguinity among ethnic groups is not uncommon, leading to hereditary conditions commonly seen only in those population subsets.